[mklimenko-nv]

Summary

Release 0.4.0, the first publishable version since 0.3.0 (2026-05-04):

• Version 0.3.0 -> 0.4.0. Everything since 0.3.0 is additive except that the onnx and protos modules now sit behind the default-on onnx feature (Make ONNX support optional #13), which changes the surface for default-features = false consumers; hence a minor bump.
• webnn-onnx-utils is taken from crates.io (0.1.1, identical to its main branch): cargo publish rejects git dependencies, so this is what has blocked publishing.
• exclude for examples/resnet_head.weights: the file is 8 MiB of the 8.8 MiB package, against crates.io's 10 MiB cap. The package is now 76 files, 989 KiB. The example still works from a checkout.
• repository metadata (cargo warned it was missing).
• CHANGELOG: the top entry still read [0.3.0] - to be released; it is dated, and a [0.4.0] section covers Make ONNX support optional #13, docs: fix link in README #14, Add missing ops for ResNet-50 #16, Add packed 4-bit SafeTensors weight support #19, Add ONNX Softplus import and shape propagation #21 and Support ONNX opset 20 and faithful tanh GELU lowering #23.
• publish.yml: fails when the release tag does not match the Cargo.toml version, and the publish step now names this crate instead of rustnn.

Validation

• make fmt-check, make lint, make test: clean, 220 tests pass with default features and 73 with --no-default-features (the CI minimal matrix).
• cargo publish --dry-run --allow-dirty: packages and verifies.

Release steps

Merge, tag v0.4.0, create the GitHub release; publish.yml publishes. rustnn (release/0.6.0) and pywebnn then switch their webnn-graph dependency from the git branch to "0.4".